Fig. 1

Morphologic and immunophenotypic findings of lymphoma in Case 1. The neoplastic lymphoid cells infiltrated diffusely with vague nodules in (A); they were small to medium in size and by immunostaining; they were positive for CD20 in (B); quantities of perifollicular T-cell infiltrates that were PD1-positive were seen in (C); the follicular dendritic cell meshwork mainly confined to follicles were also shown by CD21 in (D); by in situ hybridization with Epstein–Barr virus-encoded small RNAs, rare small positive cells (E) were also noted